从Text获取CGPath [英] Get CGPath from Text

问题描述

Hej研究员，

我正在尝试将一个字母和/或多个字母转换为CGPathRef，以便手动将它们绘制到自定义UIView中。我尝试过CoreText和Framesetters，包括这个小片段，但它似乎不起作用....

I'm currently trying to convert a letter and/or multiple of them to a CGPathRef for manually drawing them into a custom UIView. I tried the way over CoreText and Framesetters including this little snippet but it doesn't seem to work....

NSAttributedString *stringToDraw = [[NSAttributedString alloc] initWithString:content
                                                                       attributes:nil];

    // now for the actual drawing
    CGContextRef context = UIGraphicsGetCurrentContext();

    // flip the coordinate system

    // draw
    CTFramesetterRef frameSetter = CTFramesetterCreateWithAttributedString((__bridge CFAttributedStringRef)stringToDraw);
    CTFrameRef frame = CTFramesetterCreateFrame(frameSetter, CFRangeMake(0, 0), NULL, NULL);

    return CTFrameGetPath(frame);

推荐答案

CTFrameGetPath 返回限定 CTFrame 的路径，而不是绘制框架生成的路径。我假设您正在执行上述操作，因为您正在缓存路径以改善以后的绘图性能？ （因为 CTFrame 可以很容易地将自己绘制到自定义视图中。）

CTFrameGetPath returns the path the circumscribes the CTFrame, not the path generated by drawing the frame. I assume that you're doing the above because you are caching the paths to improve later drawing performance? (Since CTFrame can easily draw itself into a custom view).

如果你真的想要获得 CGPath ，你需要一直钻到 CGGlyph ，然后使用 CTFontCreatePathForGlyph 。如果你只是想快速重绘文字，我可能会把它画成 CGLayer （不是 CALayer ） code> CTFrameDraw 供以后重复使用。

If you really want to get CGPath, you need to drill all the way down to the CGGlyph and then use CTFontCreatePathForGlyph. If you just want to quickly redraw text, I'd probably draw this into a CGLayer (not CALayer) with CTFrameDraw for later reuse.

如果你真的想要 CGPath 对于字形，请查看低级文本呈现。您需要的代码就在那里。

If you still really want the CGPath for the glyphs, take a look at Low-level text rendering. The code you need is in there.

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